From: Lower Saxony Germany
first read this thread.
I found it very helpful.
Don't let your units wander too far away from their HQ's, esp when they have left the roads. Getting stuck in the mountains, swamps or plains can really drain the AP. You have to move your army to help a stuck division then.
Try to move your HQ with your army. The units fight better when the HQ is right behind them, 3 hexes radius. (If I remember correctly)
Mech forces, air forces and navies really suck up your supplies. Try putting your rear forces on 50% supplies till they reach the frontline. Remember to make a note of this otherwise they won't be getting enough bullets when the make contact with the enemy. Change to 100% before it's too late.
Also mentioned in the thread above.
I hope I could help you out.
"It is not enough to expect a man to pay for the best, you must also give him what he pays for." Alfred Dunhill